The present invention relates to an improvement for EEMPI system, [EEMPI system, namely EKG and EEG Multiphase Information Diagnoser, (U.S. Patent Pending: Ser. No. 07/397,695 filed Oct. 30, 1989, and its CIP Ser. No. 07/822,525, filed Jan. 17, 1992, and also its CIP Ser. No. 07/994,492, filed Dec. 21, 1992, entitled Method of and Arrangement for Diagnosing Heart and Brain Disease.), is a device which could early detect, in a non-invasive manner, heart disease (especially coronary heart disease) before it can be detected by conventional methods], provides its remote usage and remote processing the data through computer network.
Dysfunction of the heart is still the leading cause of death in the world. About 48% of death in the U.S.A are caused by heart dysfunction. One of the major problems that had not been solved is the early detection of heart disease prior to the serious stages, such as a heart attack, at a time when the disease can be treated and progression might be rewarded or halted. Unfortunately, the conventional EKG can display normal results even in the presence of a patient's advanced coronary artery disease. The conventional EKG is neither sensitive nor specific enough to detect coronary artery disease which has led up to 50% of patients with occlusive coronary artery disease have been reported to have a normal conventional EKG.
Over the years many approaches have been utilized to extract information from the EKG regarding myocardial ischemia. Most of these techniques have been restricted to analysis in the time domain. More recently, in EKG field analysis involving quantification of the frequency content (such as power spectrum) or amplitude histogram of portions of EKG have been utilized. But all these transformations were used independently and have not been synthesized as an integral system. Plus some useful or new transformations, (i.e. transfer function, impulse response etc.), still have not been utilized in EKG field yet.
Since EKG signals arise from the discharge of hundreds of thousands of electrically active cells, they produce a complicated resultant complex electrical signal. This leads to challenging signal processing problems that conventional time and frequency domain analysis and isolated transformation analysis fail to address, since information regarding non-linearities, cross correlations, coherences, transmissions, phase relationships and the integral effect of all these factors combined are suppressed.
To solve this problem, a Multiphase Information Analysis techniques (MPI) is necessary. The definition of MPI is: an information analysis method which, by using a series of appropriate transformations (namely phases), transforms the original date (e.g. EKG) to a series of functions (namely MPI functions or MPI phases) such as power spectrum, transfer function, coherence, impulse response, cross correlation, and amplitude histogram, etc., then uses these MPI functions synthetically together and integrated as a system to extract the information which is difficult to be drawn with conventional methods. MPI is the main principle behind the EEMPI system. [Note: a series of functions are namely a series of phases, so this analysis method is called "Multiphase Information Analysis" (MPI) and the system for analyzing EKG (ELECTROCARDIOGRAM) and EEG (ELECTROENCEPHELOGRAM) is called EEMPI system (i.e. EKG AND EEG MULTIPHASE INFORMATION ANALYSIS SYSTEM)].
The definitions of the transformations used by EEMPI system are as follows:
The power spectrum function is calculated as follows: The auto power spectrum G.sub.xx (f) for lead V5, the signals of the chest lead of EKG(electrocardiogram), is determined from equation (1): EQU G.sub.xx (f)=S.sub.x (f).multidot.S.sub.x (f)* (1)
where S.sub.x (f) is the Fourier transform of the time-dependent, lead V5 signal f.sub.x (t), and where S.sub.x (f)* is the complex conjugate. For the power spectrum, the power is plotted against frequency.
The auto power spectrum G.sub.yy (f) for lead II is determined from equation (2): EQU G.sub.yy (f)=S.sub.y (f).multidot.S.sub.y (f)* (2)
where S.sub.y (f) is the Fourier transform of the time-dependent, lead II signal, the signals of EKG limb lead, f.sub.y (t), and where S.sub.y (f)* is the complex conjugate.
The phase shift function is calculated as follows: First, the amplitude ratio of the transfer function H.sub.xy (f) is determined from equation (3): EQU H.sub.xy (f)=G.sub.xy (f)/G.sub.xx (f) (3)
where the cross power spectrum: EQU G.sub.xy (f)=S.sub.x (f).multidot.S.sub.y (f)* (4)
and where G.sub.xx (f) is obtained in equation (1).
Second, the phase shift .theta..sub.xy (f) of the transfer function H.sub.xy (f) is determined from equation (5): EQU .theta..sub.xy (f)=tan.sup.-1 {[IM(H.sub.xy (f))]/[RE(H.sub.xy (f))]56 (5)
where IM and RE are the imaginary and real parts of the transfer function.
The phase shift is a measure of the time difference between the left ventricular and whole heart signals and is plotted against frequency. Phase leads and lags are respectively indicated above and below the reference line, the base line.
The impulse response function is calculated as follows: The Impulse response IH.sub.x (f) is determined from equation (6): EQU IH.sub.x (f)=F.sup.-1 H.sub.xy (f) (6)
where F.sup.-1 is the inverse Fourier transform of the transfer function H.sub.xy (f) defined in equation (3).
The impulse response is a measure of the output response of the heart solely in response to the input of the left ventricular signal and is plotted as amplitude of impulse against the specific time T.
The amplitude histogram function is a standard statistical analysis of the amplitudes present in the left ventricular (EKG lead V5) and whole heart signals (EKG lead II), wherein the occurrence frequency is plotted against specific amplitudes. These plots indicate how many times a given amplitude is present in the left ventricular (EKG lead V5) and whole heat signals (EKG lead II).
The coherence function is calculated as follows: The coherence .gamma..sub.xy (f) is determined from equation (7): EQU .gamma..sub.xy (f)=G.sub.xy (f)/[G.sub.xx (f).multidot.G.sub.yy (f)](7)
G.sub.xy (f), G.sub.xx (f) and G.sub.yy (f) are defined in equations (4), (1) and (2). The coherence is plotted against frequency.
The cross correlation function is calculated as follows: The cross correlation .phi..sub.xy (.tau.) is determined from equation (8): ##EQU1## where f.sub.x (t) and f.sub.y (t) are the left ventricular (lead V5) and whole heart signals (lead II), whre .tau. is the delay time between the signals, and where T is the test period typically 150 seconds. The cross correlation is a measure of the correspondence of the signals and is plotted against the delay time .tau..
EEMPI system is a device which uses MPI technique to analyze EGK and EEG signals for early detecting, in a non-invasive manner, heart and brain disease before it can be detected by conventional methods. Unit now, no other device uses EMI techniques and 6 different kinds of transformations, as a system, to analyze EKG and EEG signals, therefore EEMPI is a totally new system (new invention), quite different from any other computerized EKG and conventional EKG and EEG system present today.
A specific but very important result of heart disease, especially coronary heart disease, is the heart attack and the onset of sudden death always happen unexpectedly, namely they may take place any time, and some times the attack happens in a non-symptomatic situation. This is called "silent ischemia". Therefore, it is prossible to find out the problems on time and deal with them prior to the serious stage only when the constant examination is available. This constant examination must be independent of doctors and of the hospitals, because it is difficult for every person to go to hospital and see a doctor at any time. On many occasions, it is too late for the patients to be hospitalized for the heart attack.
To achieve the goal of preventing sudden death from heart attacks and brain strokes, it is indispensable to develop an easily handled diagnostic instrument which can be used by patients themselves in the home to make an early diagnosis of heart disease especially coronary heart disease and an early warning of heart attack with constant monitoring independent of doctors or hospitals.
EEMPI is the only instrument that could be used to achieve this goal on the basis of its early diagnosis of heart disease, its easily handled by laymen, its automatically diagnosis, its light-weight and ability to be used in patient's home independent of doctors or hospitals. But it is still too expensive for the common people.
For solving this problem, one good way is to use a small piece of board to collect, amplify, A/D (analog to digit) convert the EKG data, and remotely transfer them to a diagnostic center through computer network (such as Moden System, Zoom 9600, etc.), then treat the data by the diagnostic center with EEMPI System and get the results (diagnosis of the patients), then transferring the results to the patients' (users, customers) computers to print out the results in their homes, that is the main principle of the present invention. By using of this invention, patients could use EMPI system in their homes only need to pay the cost of the collecter, amplifier, A/D converter and computer network, some software and accessories payments, that may be lower than $1,000.--which could be accepted (able burdening to pay) by most families.
It is therefore a principal object of the present invention by using computer network to remotely treat EKG and EEG data and make the EEMPI System, namely EKG and EEG Multiphase Information Diagnosis System, to be used popularly in common people's homes.
A further object of the present invention is to provide a way to remotely treat any biological and physical data (such as EMG, and many other biological and physical signals) with MPI system in a convenient condition.